Distribution and mobility of petroleum hydrocarbons in soil: case study of the South Pars Gas Complex, southern Iran

This article discusses the distribution of total petroleum hydrocarbons (TPH) contamination in soil within areas of the South Pars Gas Complex (S.P.G.C.), located on the northern shore of the Persian Gulf. To assess the potential risk to groundwater, in situ contaminant mobility was also examined in vertical soil profiles. Sampling was conducted in two rounds, and TPH was determined in accordance with standard methods of TPH analysis. The maximum detected concentration was 10268 +785 mg/kg in the area of the waste disposal site. Significant heterogeneity in natural attenuation of different hydrocarbon compounds during transport in the soil was observed. Although the groundwater samples did not show evidence of contamination, vertical contamination profiles clearly showed that groundwater contamination will occur in the near future if no remedial action is taken immediately. It is worth noting that the refineries have been brought to production just in the last 5 years. Also, relevant soil and contamination properties were investigated to recommend an appropriate remediation approach. Bioventing and biopiling were suggested as remediation technologies. However, the result of this study highlights the necessity for national regulations to address cleanup standards and the preventive and remedial guidelines for petroleum hydrocarbon contamination in soil or groundwater.